Stationary detonation combustor, and stationary detonation wave generating method

ABSTRACT

A steady-state detonation combustor and a steady-state detonation wave generating method, in which a stabilized detonation wave can be generated by generating a hypersonic and unburned premixed gas. An rich premixed gas whose gas fuel is rich is combusted in a rich premixed gas combustion chamber ( 11 ) to generate a fist high-temperature and high-pressure burned gas, while at the same time, a lean premixed gas whose oxygen is rich is combusted in a lean premixed gas combustion chamber ( 12 ) to generate a second high-temperature and high-pressure burned gas, and subsequently, after each high-temperature and high-pressure burned gas is accelerated to hypersonic speed and at the same time mixed together through an interpenetrating nozzle ( 40 ), a premixed gas obtained by the mixture and containing the gas fuel and the oxygen which are unreacted is impinged on a steady-state detonation stabilizer ( 60 ), so that a stabilized detonation wave is generated.

TECHNICAL FIELD

This invention relates to a steady-state detonation combustor and asteady-state detonation wave generating method, through which adetonation wave is generated in steady state with respect to a staticsystem, allowing a premixed gas containing a gas fuel and oxygen to becombusted, and intended particularly to be used to an aerospacepropulsion engine for an aerospace plane, a combustor for a power gasturbine, a detonation wave generator for basic researches, and so forth.

BACKGROUND ART

In general, a detonation wave is generated in such a manner that adetonation gas is encapsulated in a tube, and ignited at a tube end toinduce a transition from a deflagration wave to a detonation wave. Thedetonation wave thus generated is difficult to be applied toengineering, since it propagates at extremely high (hypersonic) speed oftwo to three km/sec with respect to a laboratory system (static system).A steady-state propagation of the detonation wave in static state withrespect to a laboratory system (static system) is a requisite for anapplication of the detonation wave, but no such apparatus has beendeveloped so far.

Meanwhile, in order to maintain a steady-state detonation wave in staticstate in an experimental apparatus, there are two issues to be cleared,as follows.

To begin with, the first issue is to develop a stabilizer to stabilize adetonation wave with respect to a hypersonic premixed gas flowing withinan experimental apparatus. Until recently, conditions to stabilize adetonation wave were uncertain among the detonation researchers, andthus development of such a stabilizer was impossible.

The second issue is to generate a premixed gas itself which is bothhypersonic and unburned. This is deemed as an extremely difficult issue.Because, in general, in order to generate a hypersonic flow, a method istaken in which an operating gas is brought to be high-temperature andhigh-pressure, and such an internal energy is converted to a kineticenergy through a nozzle. However, when an unburned premixed gas isaccelerated in the same manner, combustion takes place at a stage wherethe operating gas (unburned premixed gas) is brought to behigh-temperature, so that the hypersonic flow that is generated isalready in a state of completely burned. To cope with this, a method iscontemplated in which a gas fuel (combustible gas) and oxygen areseparately brought to be high-temperature, accelerated to be hypersonic,and mixed together thereafter. However, in this method, although the gasfuel and oxygen do not begin to react upon the acceleration as they areseparate in becoming high-temperature, the time period necessary for thesubsequent mixture becomes longer than a characteristic time of flow,meaning that the mixture itself is difficult. Also, an expensive heatingapparatus is required to make the operating gas high-temperature andhigh-pressure, which is another problem.

Accordingly, it is an object of the present invention to provide asteady-state detonation combustor and a steady-state detonation wavegenerating method which allow generation of a stabilized detonation waveby generating a premixed gas which is both hypersonic and unburned.

DISCLOSURE OF THE INVENTION

The present invention includes a steady-state detonation combustor tocombust a premixed gas containing a gas fuel and oxygen in such a mannerthat a detonation wave is generated in steady state with respect to astatic system, where the steady-state detonation combustor includes: arich premixed gas combustion chamber to combust a detonative richpremixed gas with the gas fuel being rich with respect to the oxygen; alean premixed gas combustion chamber to combust a detonative leanpremixed gas with the gas fuel being lean with respect to the oxygen; aninterpenetrating nozzle including a plurality of nozzles arranged in aninterpenetrating manner with each other, in which a firsthigh-temperature and high-pressure burned gas containing an unreactedgas fuel obtained by combusting the rich premixed gas in the richpremixed gas combustion chamber and a second high-temperature andhigh-pressure burned gas containing an unreacted oxygen obtained bycombusting the lean premixed gas in the lean premixed gas combustionchamber, respectively accelerated to hypersonic speed such that theirstatic temperatures descend and they are mixed together; and asteady-state detonation stabilizer arranged at a position which bars aflow of a premixed gas containing the unreacted gas fuel and unreactedoxygen obtained by mixing the first high-temperature and high-pressureburned gas and the second high-temperature and high-pressure burned gasthrough the interpenetrating nozzle, to combust the premixed gas bygenerating an stabilized detonation wave through impingement of thepremixed gas flowing at hypersonic speed through the interpenetratingnozzle.

Here, the number of nozzles constituting the “interpenetrating nozzle”is preferably two in light of structural simplification, but it is not alimitation, so that, for example, four nozzles, six nozzles, eightnozzles, and so forth, or odd-numbered nozzles may be used, meaning thatat least two nozzles, including one nozzle through which the firsthigh-temperature and high-pressure burned gas passes, and the othernozzle through which the second high-temperature and high-pressureburned gas passes, are arranged in an interpenetrating manner to eachother to allow mixture of the first high-temperature and high-pressureburned gas and the second high-temperature and high-pressure burned gas.

Further, “the position that bars flow of the premixed gas” at which “thesteady-state detonation stabilizer” is arranged is a position where astagnation region or a subsonic region having a certain area or greatercan be formed with respect to the stabilizer. Accordingly, “thesteady-state detonation stabilizer” is an obstruction object in a mannerof decreasing the cross sectional area of the flow path, by which thespeed of the premixed gas flowing at hypersonic speed is decelerated.

In such a steady-state detonation combustor according to the presentinvention, the rich premixed gas is combusted in the rich premixed gascombustion chamber to generate the first high-temperature andhigh-pressure burned gas containing the unreacted gas fuel, while thelean premixed gas is combusted in the lean premixed gas combustionchamber to generate the second high-temperature and high-pressure burnedgas containing the unreacted oxygen, and thereafter, these first andsecond high-temperature and high-pressure burned gases are acceleratedand mixed through the interpenetrating nozzle. In other words, the richpremixed gas and the lean premixed gas are prepared, and these richpremixed gas and lean premixed gas are combusted in separate combustionchambers respectively to be high-temperature and high-pressure, so thatthe first and second high-temperature and high-pressure burned gaseswhich, in spite of being high-temperature and high-pressure,respectively include the unreacted gas fuel and the unreacted oxygen aregenerated, which are then accelerated and mixed through theinterpenetrating nozzle. Then, after that, the accelerated and mixed gasis impinged on the steady-state detonation stabilizer, whereby adetonation wave is generated.

Accordingly, the disadvantage of the prior arts that the combustion isalready completed at a stage of making the operating gashigh-temperature in order to obtain a hypersonic flow can be eliminated,allowing generation of a premixed gas which is both hypersonic andunburned, whereby the above-described second issue can be cleared.

Further, the chemical energy of the gas can be separated into a heatenergy for generating a hypersonic flow and an exothermic reaction inthe detonation wave, so that the generation of the hypersonic flow andthe generation of the detonation wave come to be possible with anextremely simple structure and at a low cost.

Furthermore, since quantitative conditions for stabilizing thedetonation wave are identified and the steady-state detonationstabilizer is arranged in a manner of fulfilling such conditions, thedetonation wave can be generated in steady state with respect to astatic system and kept as it is, whereby the above-described first issuecan be cleared.

Further, the use of the interpenetrating nozzle promotes the mixture andat the same time accelerates the flow, avoiding an inconvenience of themixture time being longer than the characteristic time of the flow,whereby the above-described object can be achieved.

Furthermore, it is preferable that the above-described steady-statedetonation combustor is structured such that it is provided withsimultaneous ignition apparatuses to simultaneously inject ahigh-temperature combustion gas jet into the rich premixed gascombustion chamber and the lean premixed gas combustion chamber, inwhich the simultaneous ignition apparatuses include: a simultaneousignition chamber to encapsulate a detonative equivalent premixed gaswhich contains a gas fuel and oxygen mixed at an equivalence ratio of1.0; an igniter to ignite the equivalent premixed gas encapsulated inthe simultaneous ignition chamber; and injection controllersrespectively provided between the simultaneous ignition chamber and therich premixed gas combustion chamber, and between the simultaneousignition chamber and the lean premixed gas combustion chamber, allowingthe high-temperature and high-pressure gas obtained by combusting theequivalent premixed gas in the simultaneous ignition chamber to besimultaneously injected into the rich premixed gas combustion chamberand the lean premixed gas combustion chamber as a high-temperaturecombustion gas jet, so that the rich premixed gas and lean premixed gasin each combustion chamber can be ignited simultaneously.

Here, the “injection controller” is preferably an openable and closablevalve in the case the injection is repeated, but where the injection isneeded only once, a diaphragm, for example, may be provided which isburst through to inject the high-temperature combustion gas jet when thepressure of the gas in the simultaneous ignition chamber reaches acertain level.

Further, the ignition using the “igniter” is preferably performedthrough discharge.

If a simultaneous ignition apparatus is provided, a simultaneousignition of the rich premixed gas in the rich premixed gas combustionchamber and the lean premixed gas in the lean premixed gas combustionchamber can assuredly be realized.

Further, the rich premixed gas and the lean premixed gas in theabove-described steady-state detonation combustor are preferably any onetype of mixed gases among a mixed gas of hydrogen and oxygen, a mixedgas of hydrocarbon of methane series including methane, ethane, propane,butane, pentane, and hexane and oxygen, a mixed gas of hydrocarbon ofethylene series including ethylene and propylene and oxygen, a mixed gasof acetylene and oxygen, or a mixed gas of ammonia and oxygen.

Furthermore, in the above-described steady-state detonation combustor,it is preferable that an equivalence ratio of the gas fuel with respectto the oxygen in the rich premixed gas is 1.2-2.0, and an equivalenceratio of the gas fuel with respect to the oxygen in the lean premixedgas is 0.3-0.8.

Moreover, in the above-described steady-state detonation combustor, itis preferable that a ratio of the volume of the lean premixed gascombustion chamber with respect to the volume of the rich premixed gascombustion chamber is 0.5-2.0.

Further, in the above-described steady-state detonation combustor, aratio of the volume capacity of the simultaneous ignition chamber withrespect to the total volume capacity of the rich premixed gas combustionchamber and the lean premixed gas combustion chamber is preferably1/5-1/30.

Furthermore in the above-described steady-state detonation combustor, itis preferable that: the ratio of the cross sectional area of theinterpenetration starting point with respect to the cross sectional areaof the throat portion of the interpenetrating nozzle is preferably 10 orgreater; the ratio of the cross sectional area of the outlet portionwith respect to the cross sectional area of the throat portion is 25 orgreater; and the cross sectional area of the interpenetration startingpoint is smaller than the cross sectional area of the outlet portion.Here, the cross sectional area of the throat portion is a sum of crosssectional areas of each throat portion of the plural nozzlesconstituting the interpenetrating nozzle. So long as these relationshipsare kept, areas of each cross section constituting the interpenetratingnozzle may be expanded monotonically and smoothly from the throatportion to the outlet portion, and a plane forming the interpenetratingnozzle may be an arbitrary curved plane.

The “interpenetrating nozzle” having such a preferable structure can beformed by an arbitrary curved plane so long as the above conditions arefulfilled, however, from the standpoint of structural simplification,manufacturing facilitation, and the like, the following aninterpenetrating nozzle formed by a pair of cone-shaped nozzles inparallel and interpenetrating can be cited as a tangible structuralexample which is particularly preferable.

For example, cited is an interpenetrating nozzle which includes twoidentically shaped cone nozzles, with each outlet portion and eachthroat portion thereof being arranged on the same plane, and axes ofeach cone nozzle being arranged in parallel, such that each cone nozzleis interpenetrating, with the interpenetrating portion being cut out(for example, as in the cases of FIG. 2 and FIG. 3 referred to later).

Further, cited as an interpenetrating nozzle of another structure is onewhich includes two identically shaped, isosceles-triangle plate nozzles,with each outlet portion and each throat portion of these plate nozzlesarranged on a same plane and center lines of each plate nozzle beingarranged in parallel, thus allowing the plate nozzles to interpenetrateeach other, with the interpenetrating portion being cut out (forexample, as in the case of FIG. 8 referred to later and the like).

Furthermore, envisaged as the “steady-state detonation stabilizer” arean external flow type stabilizer in which a gas flows externally(circumferentially) with respect to an obstruction object, and aninternal flow type stabilizer in which a gas flows internally withrespect to an obstruction object, and more specifically, ones having thefollowing structures can be presented.

As an example of an external flow type structure, a steady-statedetonation stabilizer can be cited whose tip portion receiving a flow ofa premixed gas passing through the interpenetrating nozzle ishemispheric, and a supporting portion supporting the hemispheric tipportion is cylindrical (for example, as in the case of FIG. 4 referredto later).

Further, as another external flow type structure, a steady-statedetonation stabilizer can be cited whose tip portion receiving a flow ofa premixed gas passing through the interpenetrating nozzle is conicaland a supporting portion supporting said conical tip portion iscylindrical (for example, as in the case of FIG. 9 referred to later).

Furthermore, as still another external flow type structure, cited is asteady-state detonation stabilizer whose tip portion receiving a flow ofa premixed gas passing through the interpenetrating nozzle is polygonalcone shaped, and a supporting portion supporting the polygonal coneshaped tip portion is polygonal column shaped (for example, as in thecase of FIG. 10 referred to later and the like). Here, the polygonalcone shape includes a pyramid shape having any angles of three or more,such as triangular pyramid, quadrangular pyramid, pentagonal pyramid,hexagonal pyramid, and so forth, while the polygonal column shapeincludes a columnar shape having any angles of three or more, such astriangular prism, square prism, pentagonal prism, hexagonal prism, andso forth.

On the other hand, presented as an internal flow type structure is asteady-state detonation stabilizer which includes two two-dimensionalwedges arranged oppositely to each other, with each peak portion ofthese two-dimensional wedges being arranged on a same plane which isorthogonal to a flow direction of the premixed gas passing through theinterpenetrating nozzle (for example, as in the case of FIG. 11 referredto later and the like).

Further, presented as another internal flow type structure is asteady-state detonation stabilizer which includes two conical,convergent to divergent shaped nozzles arranged in a manner that theirconvergent portions are coupled on each other, with each axis of theseconvergent to divergent shaped nozzles coinciding, and each axis beingarranged in a direction along a flow direction of the premixed gaspassing through the interpenetrating nozzle (for example, as in the caseof FIG. 12 referred to later).

Further, the present invention includes a steady-state detonation wavegenerating method to generate a detonation wave in steady state withrespect to a static system, which is characterized in that a detonativerich premixed gas with its gas fuel being in a rich state with respectto the oxygen, is infused into a rich premixed gas combustion chamber,while at the same time a detonative lean premixed gas, with its gas fuelin a lean state with respect to the oxygen, is infused into a leanpremixed gas combustion chamber, and by simultaneously igniting theserich premixed gas and lean premixed gas, the rich premixed gas iscombusted in the rich premixed gas combustion chamber to generate afirst high-temperature and high-pressure burned gas containing anunreacted gas fuel, while at the same time the lean premixed gas iscombusted in the lean premixed gas combustion chamber to generate asecond high-temperature and high-pressure burned gas containingunreacted oxygen, after which the first and the second high-temperatureand high-pressure burned gases are, by using an interpenetrating nozzlecomposed of a plurality of nozzles arranged in an interpenetratingmanner, respectively accelerated to hypersonic speed such that theirstatic temperatures descend and they are mixed together, and a premixedgas flow obtained by mixing the first and the second high-temperatureand high-pressure burned gases is barred by a static-state detonationstabilizer, such that a stabilized detonation wave can be generated.

With such a steady-state detonation wave generating method according tothe present invention, the operations and effects obtained by theabove-described steady-state detonation combustor of the presentinvention can be attained as they are, resulting in achievement of theaforementioned objects.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an overall block diagram of a steady-state detonationcombustor of an embodiment of the present invention;

FIG. 2 is a detailed block diagram of an interpenetrating nozzle of theabove-described embodiment;

FIG. 3 is a sectional view taken along the A-A line in FIG. 2;

FIG. 4 is a detailed block diagram of a steady-state detonationstabilizer of the above-described embodiment;

FIG. 5 is an explanatory view showing infusion and ignition of apremixed gas of the above-described embodiment;

FIG. 6 is an explanatory view showing acceleration and mixture of ahigh-temperature and high-pressure burned gas using the interpenetratingnozzle of the above-described embodiment;

FIG. 7 is an explanatory view showing stabilization of the detonationwave using a steady-state detonation stabilizer of the above-describedembodiment;

FIG. 8 is a detailed block diagram of an interpenetrating nozzle, whichis a modified embodiment of the present invention;

FIG. 9 is a detailed block diagram of a steady-state detonationstabilizer of an external flow type, which is a modified embodiment ofthe present invention;

FIG. 10 is a detailed block diagram of a steady-state detonationstabilizer of another external flow type, which is a modified embodimentof the present invention;

FIG. 11 is a detailed block diagram of a steady-state detonationstabilizer of an internal flow type, which is a modified embodiment ofthe present invention; and

FIG. 12 is a detailed block diagram of a steady-state detonationstabilizer of another internal flow type, which is a modified embodimentof the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

In order to describe the present invention in further detail, anexplanation will be carried out according to attached drawings hereto.

FIG. 1 shows an overall block diagram of a steady-state detonationcombustor 10 according to an embodiment of the present invention.

In FIG. 1, the steady-state detonation combustor 10 includes: a richpremixed gas combustion chamber 11 to combust a detonative rich premixedgas; a lean premixed gas combustion chamber 12 to combust a detonativelean premixed gas; a simultaneous ignition chamber 13 to encapsulate adetonative equivalent premixed gas; a rich premixed gas source 21 tosupply the rich premixed gas to the rich premixed gas combustion chamber11; a lean premixed gas source 22 to supply the lean premixed gas to thelean premixed gas combustion chamber 12; an equivalent premixed gassource 23 to supply the equivalent premixed gas to the simultaneousignition chamber 13; an igniter 30 to ignite the equivalent premixed gasencapsulated in the simultaneous ignition chamber 13; aninterpenetrating nozzle 40 to accelerate and mix each high-temperatureand high-pressure burned gas generated in the rich premixed gascombustion chamber 11 and the lean premixed gas combustion chamber 12; amixture promoting portion 50 provided at a rear flow side of theinterpenetrating nozzle 40; and a steady-state detonation stabilizer 60arranged at a rear flow side of the mixture promoting portion 50.

Further, provided halfway of a rich premixed gas supply path 24connecting the rich premixed gas source 21 and the rich premixed gascombustion chamber 11 is a valve 25 which is openable and closable,provided halfway of a lean premixed gas supply path 26 connecting thelean premixed gas source 22 and the lean premixed gas combustion chamber12 is a valve 27 which is openable and closable, and provided halfway ofan equivalent premixed gas supply path 28 connecting the equivalentpremixed gas source 23 and the simultaneous ignition chamber 13 is avalve 29 which is openable and closable.

Furthermore, provided between the simultaneous ignition chamber 13 andthe rich premixed gas combustion chamber 11 and between the simultaneousignition chamber 13 and the lean premixed gas combustion chamber 12 arecommunication paths 31, 32 respectively communicating each chamber, andprovided halfway of the communication paths 31, 32 respectively arevalves 33, 34 as injection controllers which are openable and closable.Further, the simultaneous ignition chamber 13, the igniter 30, and thevalves 33, 34 form a simultaneous ignition apparatus 35 tosimultaneously ignite the rich premixed gas and the lean premixed gas bysimultaneously injecting a high-temperature combustion gas jet from thesimultaneous ignition chamber 13 to the rich premixed gas combustionchamber 11 and the lean premixed gas combustion chamber 12.

Here, the ignition of the equivalent premixed gas by the igniter 30 isperformed by discharge for example, and so forth. The igniter 30 may bean apparatus which provides a gas with an energy density and energysufficient enough to start a combustion reaction, and for example, anignition plug for automotives and so forth can be suitably used.Further, each valve 33, 34 should be able to speedily control openingand closing thereof by forming itself by an electromagnetic valve andthe like, and should function as an injection controller tosimultaneously ignite the rich premixed gas and the lean premixed gas ineach combustion chamber 11, 12 respectively, by simultaneously injectingthe high-temperature and high-pressure gas (for example, a gas havingabout tenfold higher temperature and pressure) obtained by combustingthe equivalent premixed gas in the simultaneous ignition chamber 13 tothe rich premixed gas combustion chamber 11 and the lean premixed gascombustion chamber 12.

Further, provided between the rich premixed gas combustion chamber 11and the interpenetrating nozzle 40 and between the lean premixed gascombustion chamber 12 and the interpenetrating nozzle 40 arecommunication paths 14, 15 communicating these in-between spaces.

The rich premixed gas supplied from the rich premixed gas source 21 tothe rich premixed gas combustion chamber 11, being a detonation gas witha gas fuel and oxygen being premixed, is a gas with the gas fuel beingexcessively mixed with respect to the oxygen, in other words, a gas witha gas fuel of high concentration. An equivalence ratio of the gas fuelwith respect to the oxygen in the rich premixed gas is preferably1.2-2.0 considering, besides others, a need to appropriately separate achemical energy of the gas into a heat energy for generating ahypersonic flow and an exothermic reaction in a detonation wave.

On the other hand, the lean premixed gas supplied from the lean premixedgas source 22 to the lean premixed gas combustion chamber 12, being adetonation gas with a gas fuel being premixed with oxygen, is a gas withthe oxygen being excessively mixed with respect to the gas fuel, inother words, a gas with a gas fuel of low concentration. An equivalenceratio of the gas fuel with respect to the oxygen in the lean premixedgas is preferably 0.3-0.8 considering, besides others, a need toappropriately separate a chemical energy of the gas into a heat energyfor generating a hypersonic flow and an exothermic reaction in adetonation wave.

Further, the equivalent premixed gas supplied from the equivalent weightmixed gas source 23 to the simultaneous ignition chamber 13 is adetonation gas with a gas fuel being premixed with oxygen at anequivalence ratio of 1.0.

Furthermore, used as detonation gases for these rich premixed gas andlean premixed gas, as well as for the equivalent premixed gas are, forexample, a mixed gas of hydrogen and oxygen, a mixed gas of hydrocarbonof methane series (methane, ethane, propane, butane, pentane, andhexane) and oxygen, a mixed gas of hydrocarbon of ethylene series(ethylene, propylene) and oxygen, a mixed gas of acetylene and oxygen, amixed gas of ammonia and oxygen, and so forth. Additionally, each ofthese premixed gases may be diluted with nitrogen, a rare gas, and soforth.

A ratio of the volume capacity of the volume capacity of the leanpremixed gas combustion chamber 12 with respect to the rich premixed gascombustion chamber 11 is preferably 0.5-2.0, and for example 1.0,considering a need to make the mixture ratio of each high-temperatureand high-pressure burned gas through the interpenetrating nozzle 40appropriate, and realize a smooth continuous operation, and so forth.

Further, a ratio of the volume capacity of the simultaneous ignitionchamber 13 with respect to the summed volume capacity of the richpremixed gas combustion chamber 11 and the lean premixed gas combustionchamber 12 is preferably 1/5-1/30, and for example 1/10 or the like,considering a need to ensure ignition of the rich premixed gas and thelean premixed gas, and so forth.

Furthermore, each of volume capacities of the rich premixed gas source21, lean premixed gas source 22, and equivalent premixed gas source 23is preferably five times or more greater than each of the volumecapacities of the rich premixed gas combustion chamber 11, lean premixedgas combustion chamber 12, and simultaneous ignition chamber 13,respectively. Further, each pressure of the rich premixed gas source 21,lean premixed gas source 22, and equivalent premixed gas source 23should be set higher than the initial pressures of the rich premixed gascombustion chamber 11, lean premixed gas combustion chamber 12, andsimultaneous ignition chamber 13, respectively. Temperatures of each ofthe gas sources 21 to 23 should be 200K or higher, which may be a roomtemperature for example.

Each shape of the rich premixed gas combustion chamber 11, lean premixedgas combustion chamber 12, and simultaneous ignition chamber 13 isarbitrary and may be a cylindrical shape, for example.

FIG. 2 shows a detailed structure of the interpenetrating nozzle 40.With the interpenetrating nozzle 40, a first high-temperature andhigh-pressure burned gas containing an unreacted gas fuel obtained bycombusting the rich premixed gas in the rich premixed gas combustionchamber 11, and a second high-temperature and high-pressure burned gascontaining an unreacted oxygen obtained by combusting a lean premixedgas in the lean premixed gas combustion chamber 12, are respectivelyaccelerated to hypersonic speed such that their static temperaturesdescend and at the same time they are mixed together.

In FIG. 1 and FIG. 2, the interpenetrating nozzle 40 includes aplurality of nozzles (in the present embodiment, as an example, twonozzles) 41 and 42 in combination arranged in an interpenetratingmanner.

As shown in FIG. 2, each of nozzles 41 and 42 is a conical nozzle havingan identical shape. Each of outlet portions 41A, 42A of each of thesenozzles 41, 42 is arranged on the same plane, and at the same time, eachof throat portions thereof 41B, 42B is also arranged on the same plane.Further, axes of each of the nozzles 41, 42 are arranged in parallel.With such an arrangement, the conical surface of each of the nozzles 41,42 gradually expands from the vertex, causing an overlap, resulting information of an interpenetrating portion 43 of each of the nozzles 41,42, as shown with a chain-double dashed line in FIG. 2. Accordingly, theinterpenetrating nozzle 40 is formed such that, the interpenetratingportion 43 is cut out as a space, and a boundary line 44 between each ofthe nozzles 41, 42 is a chevron curve formed by crossing the conicalsurfaces.

FIG. 3 shows a cross section along the A-A line in FIG. 2. The positionof the A-A line is an interpenetration starting point from which theinterpenetration of the each of the nozzles 41, 42 starts, and as shownin FIG. 3, a cross section of the interpenetration starting point is ina state such that the two circular cross sections are in contact.Accordingly, the high-temperature and high-pressure burned gases of thetwo kinds do not contact each other from the throat portions 41B, 42B tothe interpenetration starting point.

A ratio of the cross sectional area of the interpenetration startingpoint (position of the A-A line) with respect to the summed crosssectional areas of the two throat portions 41B, 42B of theinterpenetrating nozzle 40 is 10 or greater, and a ratio of the crosssectional area of an outlet portion 45 (an opening portion formed byeach of the outlet portions 41A and 42A being overlapped) with respectto the summed cross sectional areas of the two throat portions 41B, 42Bis 25 or greater. Further, the cross sectional area of theinterpenetration starting point (position of the A-A line) is smallerthan the cross sectional area of the outlet portion 45. Additionally,the cross sectional area of the interpenetrating nozzle 40 at theinterpenetration starting point is determined so as to be an area withwhich the gas temperature becomes sufficiently low by the time theinterpenetration starting point is reached. Further, at the outletportion 45, the gas needs to be accelerated to speed faster than thepropagation speed of the detonation wave, and the cross sectional areaof the outlet should take a value fulfilling that condition.

In FIG. 1, the mixture promoting portion 50 is a portion to promotemixture of the gases having passed through the interpenetrating nozzle40. The cross sectional area of the mixture promoting portion 50 isgreater than the cross sectional area of the outlet portion 45 of theinterpenetrating nozzle 40. In addition, the length thereof in theflowing direction is arbitrary.

FIG. 4 shows a detailed structure of a steady-state detonationstabilizer 60. The steady-state detonation stabilizer 60 is forcombusting a premixed gas by generating a stabilized detonation wavethrough impingement of the premixed gas containing an unreacted gas fueland unreacted oxygen flowing at hypersonic speed through theinterpenetrating nozzle 40 and the mixture promoting portion 50.

In FIG. 1 and FIG. 4, the steady-state detonation stabilizer 60 isarranged in a position barring the flow of the premixed gas containingthe unreacted gas fuel and the unreacted oxygen obtained by mixing thefirst high-temperature and high-pressure burned gas and the secondhigh-temperature and high-pressure burned gas through theinterpenetrating nozzle 40, in other words, the flow of the gas passingthrough the mixture promoting portion 50 discharged from theinterpenetrating nozzle 40.

As shown in FIG. 4, the steady-state detonation stabilizer 60 includes atip portion 61 to receive a premixed gas flow (shown by an arrow “F” inthe drawing) passing through the interpenetrating nozzle 40 and themixture promoting portion 50, and a supporting portion 62 to support thetip portion 61, and is an external flow type stabilizer, meaning thatthe gas flows externally (circumferentially) with respect to thestabilizer as an obstruction object. Further, the tip portion 61 ishemispheric, and the supporting portion 62 is cylindrical.

Further, in the case of a hydrogen-oxygen premixed gas, for example, thestatic pressure of the premixed gas impinging on the tip portion 61should be set such that a Mach number at the outlet portion 45 of theinterpenetrating nozzle 40 is 5.3 or greater, and preferably six orgreater, so as to fulfill conditions to stabilize the steady-statedetonation wave around the steady-state detonation stabilizer 60, andfurther that, a detonation cell size (a size uniquely determinedaccording to the elements and state of the premixed gas; a cell width),which is the characteristic length of the detonation, becomes one fifthor smaller of the diameter of the hemispheric tip portion 61. That is tosay, the initial pressure of the premixed gas should be raised until thecell size becomes one fifth or smaller of the diameter of thehemispheric tip portion 61. Incidentally, in the case of thehydrogen-oxygen premixed gas, it is possible to form a furtherstabilized steady-state detonation wave by accelerating the premixed gasfaster than the value shown hereinabove, and by making the initialpressure of the premixed gas high.

In the present embodiment as described above, the combustion through thesteady-state detonation combustor 10 is performed as follows.

FIG. 5 shows infusing and igniting procedures of the premixed gas. It isnoted that the hatching in the drawing does not represent a crosssection, but a gas infilling state. The same applies to the subsequentFIG. 6 and FIG. 7.

In FIG. 5, first, the valves 29, 25, 27 are opened while the valves 33,34, 14, 15 are closed. The equivalent premixed gas is then infused intothe simultaneous ignition chamber 13 from the equivalent premixed gassource 23; the rich premixed gas is infused into the rich premixed gascombustion chamber 11 from the rich premixed gas source 21; the leanpremixed gas is infused into the lean premixed gas combustion chamber 12from the lean premixed gas source 22; and the valves 29, 25, 27 areclosed upon completion of all of these infusion procedures.

Subsequently, the igniter 30 is activated, and the equivalent premixedgas in the simultaneous ignition chamber 13 is ignited. After theignition, when the pressure of the equivalent premixed gas ascendssufficiently (for example, when the pressure and temperature have becomeabout tenfold higher), the valves 33, 34 are simultaneously opened, anda high-temperature combustion gas jet (shown by an arrow “J” in thedrawing) is injected simultaneously to the rich premixed gas combustionchamber 11 and lean premixed gas combustion chamber 12. With thiscombustion gas jet, the rich premixed gas in the rich premixed gascombustion chamber and the lean premixed gas in the lean premixed gascombustion chamber 12 are ignited, and the pressures and temperatures ofthese gases ascend.

Here, in the rich premixed gas combustion chamber 11, the rich premixgas is combusted, generating the first high-temperature andhigh-pressure burned gas containing the unreacted gas fuel, while in thelean premixed gas combustion chamber 12, the lean premixed gas iscombusted, generating the second high-temperature and high-pressureburned gas containing the unreacted oxygen.

FIG. 6 shows accelerating and mixing procedures of the high-temperatureand high-pressure burned gases through the interpenetrating nozzle 40.

In FIG. 6, when the valves 14 and 15 are opened with the pressures andtemperatures of the gases in each of the combustion chambers 11, 12,having ascended, the first high-temperature and high-pressure burned gasgenerated in the rich premixed gas combustion chamber 11 and the secondhigh-temperature and high-pressure burned gas generated in the leanpremixed gas combustion chamber 12 are accelerated by passing throughthe interpenetrating nozzle 40 (shown by an arrow “K” in the drawing)and mixed together (shown by a shaded part 46 in the drawing).

Here, with the divergent of the interpenetrating nozzle 40, the gas isaccelerated, and at the same time its temperature declines. It is notedthat the two high-temperature and high-pressure burned gases are not incontact from the throat portions 41B, 42B to the interpenetrationstarting point (shown in the A-A line in the FIG. 2). The temperaturesof the gases become sufficiently low by the time of reaching theinterpenetration starting point, and thereafter, posteriorly to theinterpenetration starting point, the gases are mixed throughimpingement, and at the outlet portion 45, the gases are accelerated tofaster speed than the propagation speed of the detonation wave.

FIG. 7 shows stabilization procedures of the detonation wave by thesteady-state detonation stabilizer 60.

In FIG. 7, the gases having passed through the interpenetrating nozzle40 are promotedly mixed at the mixture promotion portion 50, and afterthat, impinge on the tip portion 61 of the steady-state detonationstabilizer 60. Then, an adiabatic compression at that time ignites thegas, and a detonation wave is generated. When the operation is in steadystate, the oblique detonation wave D becomes arcuate in the neighborhoodof the tip portion 61 of the steady-state detonation stabilizer 60, andat the same time, is stabilized in a manner of spreading around in anapproximately conical shape as shown in FIG. 7.

In such a present embodiment, there are following effects. By combustingthe rich premixed gas and the lean premixed gas separately in thecombustion chambers 11, 12, to make them high-temperature andhigh-pressure, the steady-state detonation combustor 10 generates thefirst and the second high-temperature and high-pressure burned gasescontaining, in spite of both being high-temperature and high-pressure,the unreacted gas fuel and the unreacted oxygen respectively, andaccelerates and mixes them through the interpenetrating nozzle 40,resulting in elimination of an inconvenience suffered by the prior artthat the combustion is completed by the phase the temperature of theoperating gas is made high in order to obtain a hypersonic flow, meaningthat a premixed gas which is hypersonic and unburned can be generated.

As a result of this, the detonation wave can be generated by impingementof the generated premixed gas which is hypersonic and unburned on thesteady-state detonation stabilizer 60.

In addition, since the steady-state detonation combustor 10 is capableof separating the chemical energy of the gas into an internal energy forgenerating a hypersonic flow and an exothermic reaction in thedetonation wave, the generation of the hypersonic flow and thegeneration of the detonation wave can be realized with an extremelysimple structure and at a low cost.

Further, since the quantitative conditions for stabilizing thedetonation wave are identified and the steady-state detonationstabilizer 60 is arranged so as to fulfill the conditions, thedetonation wave can be generated and maintained in steady state withrespect to a static system.

In addition, the use of the interpenetrating nozzle 40 promotes mixtureand at the same time accelerates the flow, so that the inconveniencethat the mixture time becomes longer than the characteristic time offlow can be avoided.

Further, when the steady-state detonation combustor 10 is applied to agas turbine, a high thermal efficiency can be maintained (for example,the thermal efficiency can be enhanced by 30%-50%) by performingisochoric combustion while keeping the detonation wave in a combustor ofthe gas turbine, so that the efficiency of the gas turbine can bedramatically improved. That is to say, when a thermal energy isabstracted by combusting a chemical fuel in the combustion chamber ofthe gas turbine, in general, the combustion is in a constant pressure(constant pressure combustion), however, the thermal efficiency (theratio of work which can be abstracted with respect to the thermal energyprovided to a system) of a combustion process at a constant volume(isochoric combustion) compared to the constant pressure combustionprocess is dramatically higher. Furthermore, the gas turbine can bemicrominiaturized since the detonation wave is in ultra high-speedcombustion (a combustion having a propagation speed of 100-10,000 timesfaster than the normal flame).

Further, since the simultaneous ignition apparatus 35 is provided, thesimultaneous ignition of the rich premixed gas in the rich premixed gascombustion chamber 11 and the lean premixed gas in the lean premixed gascombustion chamber 12 can be assuredly realized.

Furthermore, since openable and closable valves 33, 34 are employed asinjection controllers forming the simultaneous ignition apparatus 35,injection can be repeated.

It should be noted that the present invention is not limited to theabove-described embodiment, and includes therein any modification andthe like within a range allowing the object of the present invention tobe achieved.

That is to say, in the above-described embodiment, the interpenetratingnozzle 40 is formed in combination of two identically-shaped conicalnozzles 41, 42, however, the interpenetrating nozzle of the presentinvention is not limited to be thus structured, and maybe aninterpenetrating nozzle 100 as shown in FIG. 8, for example. In FIG. 8,the interpenetrating nozzle 100 includes two identically-shaped,isosceles-triangle plate nozzles 101, 102. Each of outlet portions 101A,102A of the plate nozzles 101, 102 is arranged on the same plane, whileeach of throat portions 101B, 102B is arranged on the same plane.Further, center lines of each of the plate nozzles 101, 102 are arrangedin parallel with each other. Furthermore, the interpenetrating nozzle100 is formed such that interpenetrating portions 103 shown inchain-double dashed lines in the drawing are cut out.

Further, in the above-described embodiment, as shown in FIG. 4, in thesteady-state detonation stabilizer 60, the tip portion 61 ishemispheric, and the supporting portion 62 is cylindrical, however, thestructure of the steady-state detonation stabilizer is not limited to beas such, and essentially, the steady-state detonation stabilizer may beany obstruction object which decelerates the speed of a gas flowing inthe hypersonic speed by minifying its cross section area of the flowingpath, since, to sum up, generation of the detonation wave requiresconversion into the thermal energy by decelerating the speed of the gaspassing through the interpenetrating nozzle 40, raising its temperatureand igniting it, while maintenance of the detonation wave requires astagnation region or a subsonic region having an area of certain area orgreater. Accordingly, for example, steady-state detonation stabilizers200, 210, 220, 230 shown in FIG. 9 to FIG. 12, and so forth, are alsoacceptable.

In FIG. 9, the steady-state detonation stabilizer 200 is an externalflow type stabilizer, with its tip portion 201 being conical and itssupporting portion 202 being cylindrical.

In FIG. 10, the steady-state detonation stabilizer 210 is an externalflow type stabilizer, with its tip portion 211 being polygonal coneshaped (for example, quadrangular pyramid shaped) and its supportingportion 212 is polygonal column shaped (for example, quadratic prismshaped).

In FIG. 11, the steady-state detonation stabilizer 220 is an internalflow type stabilizer, and includes two two-dimensional wedges 221, 222arranged oppositely to each other. Each of peak portions 223, 224 ofthese two-dimensional wedges 221, 222 is arranged on a same plane whichis orthogonal to a flow direction of a premixed gas passing through theinterpenetrating nozzle 40 (a direction shown by an arrow “F” in thedrawing). Further, if each of the nozzles 41, 42 forming theinterpenetrating nozzle 40 is arranged in the horizontal direction, eachof the two-dimensional wedges 221, 222 is arranged in a directionorthogonal thereto, that is to say, in a vertical direction.

In FIG. 12, the steady-state detonation stabilizer 230 is an internalflow type stabilizer, and includes two conical and convergent todivergent shaped nozzles 231, 232 such that their respective convergentportion are coupled (hourglass-shaped). The axes of the convergent todivergent shaped nozzles 231, 232 coincide, and at the same time, eachof the axes is arranged in a direction along a flow direction of apremixed gas passing through the interpenetrating nozzle 40 (thedirection shown by the arrow “F” in the drawing).

Industrial Availability

As has been described, the steady-state detonation combustor and thesteady-state detonation wave generating method are suitable to beapplied to, for example, an aerospace propulsion engine for an aerospaceplane, a combustor for a power gas turbine, a detonation wave generatorfor basic researches, and so forth.

1. A steady-state detonation combustor to combust a premixed gascontaining a gas fuel and oxygen by generating a detonation wave insteady state with respect to a static system, said steady-statedetonation combustor comprising: a rich premixed gas combustion chamberto combust a detonative rich premixed gas in which the gas fuel is in arich state with respect to the oxygen; a lean premixed gas combustionchamber to combust a detonative lean premixed gas in which the gas fuelis in a lean state with respect to the oxygen; an interpenetratingnozzle including a plurality of nozzles arranged in an interpenetratingmanner, in which a first high-temperature and high-pressure burned gascontaining the gas fuel which is unrecated obtained by combusting therich premixed gas in said rich premixed gas combustion chamber, and asecond high-temperature and high-pressure burned gas containing theoxygen which is unreacted obtained by combusting said lean premixed gasin said lean premixed gas combustion chamber, are respectivelyaccelerated to hypersonic speed, such that their static temperaturesdescend and at the same time they are mixed together; and a steady-statedetonation stabilizer arranged at a position which bars a flow of apremixed gas containing the unreacted gas fuel and the unreacted oxygenobtained by mixing the first high-temperature and high-pressure burnedgas and the second high-temperature and high-pressure burned gas throughsaid interpenetrating nozzle, in which the premixed gas is combusted bygenerating, through impingement of the premixed gas flowing athypersonic speed through the interpenetrating nozzle, the detonationwave which is stabilized.
 2. The steady-state detonation combustoraccording to claim 1, further comprising a simultaneous ignitionapparatus to inject a high-temperature combustion gas jet simultaneouslyto said rich premixed gas combustion chamber and said lean premixed gascombustion chamber, wherein said simultaneous ignition apparatusincludes a simultaneous ignition chamber to encapsulate a detonativeequivalent premixed gas which contains the gas fuel and the oxygen mixedat an equivalence ratio of 1.0, an igniter to ignite the equivalentpremixed gas encapsulated in said simultaneous ignition chamber, and aninjection controller respectively provided between the simultaneousignition chamber and said rich premixed gas combustion chamber, andbetween the simultaneous ignition chamber and said lean premixed gascombustion chamber, wherein the injection controller is structured suchthat a high-temperature and high-pressure gas obtained by combusting theequivalent premixed gas in the simultaneous ignition chamber issimultaneously injected into said rich premixed gas combustion chamberand said lean premixed gas combustion chamber as a high-temperaturecombustion gas jet, so that the rich premixed gas and the lean premixedgas in each combustion chamber can be ignited simultaneously.
 3. Thesteady-state detonation combustor according to claim 2, wherein theinjection controller is an openable and closable valve, and ignition bythe igniter is performed by discharge.
 4. The steady-state detonationcombustor according to claim 1, wherein the rich premixed gas and thelean premixed gas are any one type of mixed gases among a mixed gas ofhydrogen and oxygen, a mixed gas of hydrocarbon of methane seriesincluding methane, ethane, propane, butane, pentane, and hexane andoxygen, a mixed gas of hydrocarbon of ethylene series including ethyleneand propylene and oxygen, a mixed gas of acetylene and oxygen, or amixed gas of ammonia and oxygen.
 5. The steady-state detonationcombustor according to claim 1, wherein an equivalence ratio of the gasfuel with respect to the oxygen in the rich premixed gas is 1.2-2.0, andan equivalence ratio of the gas fuel with respect to the oxygen in saidlean premixed gas is 0.3-0.8.
 6. The steady-state detonation combustoraccording to claim 1, wherein a ratio of a volume capacity of said leanpremixed gas combustion chamber with respect to a volume capacity ofsaid rich premixed gas combustion chamber is 0.5-2.0.
 7. Thesteady-state detonation combustor according to claim 2, wherein a ratioof a volume capacity of the simultaneous ignition chamber with respectto a total volume capacity of said rich premixed gas combustion chamberand said lean premixed gas combustion chamber is 1/5-1/30.
 8. Thesteady-state detonation combustor according to claim 1, wherein a ratioof a cross sectional area of an interpenetration starting point withrespect to a cross sectional area of a throat portion of saidinterpenetrating nozzle is 10 or greater, a ratio of a cross sectionalarea of an outlet portion with respect to the cross sectional area ofthe throat portion is 25 or greater; and the cross sectional area of theinterpenetration starting point is smaller than the cross sectional areaof the outlet portion.
 9. The steady-state detonation combustoraccording to claim 8, wherein said interpenetrating nozzle includes twoidentically shaped cone nozzles, with each outlet portion and eachthroat portion of the cone nozzles being arranged respectively on a sameplane, and axes of the cone nozzles being arranged in parallel, suchthat each of the cone nozzles is interpenetrating, with theinterpenetrating portion being cut out.
 10. The steady-state detonationcombustor according to claim 8, wherein said interpenetrating nozzleincludes two identically shaped, isosceles-triangle plate nozzles, witheach outlet portion and each throat portion of the plate nozzles beingarranged respectively on a same plane and center lines of each platenozzle being arranged in parallel, thus allowing the plate nozzles tointerpenetrate each other, with the interpenetrating portion being cutout.
 11. The steady-state detonation combustor according to claim 1,wherein, in said steady-state detonation stabilizer, a tip portionreceiving a flow of a premixed gas passing through said interpenetratingnozzle is hemispheric, and a supporting portion supporting thehemispheric tip portion is cylindrical.
 12. The steady-state detonationcombustor according to claim 1, wherein, in said steady-state detonationstabilizer, a tip portion receiving a flow of a premixed gas passingthrough said interpenetrating nozzle is conical and a supporting portionsupporting the conical tip portion is cylindrical.
 13. The steady-statedetonation combustor according to claim 1, wherein, in said steady-statedetonation stabilizer, a tip portion receiving a flow of a premixed gaspassing through said interpenetrating nozzle is polygonal cone shaped,and a supporting portion supporting the polygonal cone shaped tipportion is polygonal column shaped.
 14. The steady-state detonationcombustor according to claim 1, wherein said steady-state detonationstabilizer includes two two-dimensional wedges arranged oppositely toeach other, with each peak portion of the two-dimensional wedges beingarranged on a same plane which is orthogonal to a flow direction of thepremixed gas passing through said interpenetrating nozzle.
 15. Thesteady-state detonation combustor according to claim 1, wherein saidsteady-state detonation stabilizer includes two conical, convergent todivergent shaped nozzles arranged such that convergent portions thereofare coupled on each other, with each axis of the convergent to divergentshaped nozzles coinciding, and each axis being arranged in a directionalong a flow direction of the premixed gas passing through saidinterpenetrating nozzle.
 16. A steady-state detonation wave generatingmethod in which a detonative detonation wave is generated in steadystate with respect to a static system, said method comprising the stepsof: infusing a detonative rich premixed gas whose gas fuel is rich withrespect to oxygen to a rich premixed gas combustion chamber, while atthe same time infusing a detonative lean premixed gas whose gas fuelbeing lean with respect to the oxygen to an lean premixed gas combustionchamber; combusting, by simultaneously igniting the rich premixed gasand the lean premixed gas, the rich premixed gas in the rich premixedgas combustion chamber to generate a first high-temperature andhigh-pressure burned gas containing the gas fuel which is unreacted,while at the same time combusting the lean premixed gas in the leanpremixed gas combustion chamber to generate a second high-temperatureand high-pressure burned gas containing the oxygen which is unreacted;accelerating, by using an interpenetrating nozzle which includes aplurality of nozzles arranged in an interpenetrating manner, the firstand second high-temperature and high-pressure burned gases respectivelyto hypersonic speed such that their static temperatures descend and theyare mixed together; and barring a premixed gas flow obtained by mixingthe first and the second high-temperature and high-pressure burned gasesby a steady-state detonation stabilizer, such that a stabilizeddetonation wave is generated.
 17. A steady-state detonation combustor tocombust a premixed gas containing a gas fuel and oxygen by generating adetonation wave in steady state with respect to a static system,comprising: a rich premixed gas combustion chamber to combust adetonative rich premixed gas in which said gas fuel is in a rich statewith respect to said oxygen; a lean premixed gas combustor to combust adetonative lean premixed gas in which said gas fuel is in a lean statewith respect to said oxygen; and interpenetrating nozzles including aplurality of nozzles arranged in an interpenetrating manner, in which afirst high-temperature and high-pressure burned gas containing saidunreacted gas fuel obtained by combusting said rich premixed gas in saidrich premixed gas combustion chamber, and a second high-temperature andhigh-pressure burned gas containing said unreacted oxygen obtained bycombusting said lean premixed gas in said lean premixed gas combustionchamber, are respectively accelerated to hypersonic speed, such thattheir static temperatures descend and at the same time they are mixedtogether.